Circuit interrupter



June 17, 1947. R. c. VAN SICKLE C IRCUIT INTERRUPTER 2 Sheets$heet 1 Filed July 20, 1944 INVENTOR Eoswefl C. Kanfi'cK/e WITNESSES:

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INVENTOR 05we//C. Vanfi'cK/e Patented June 17, 1947 CIRCUIT IN TERRUPTER Roswell C. Van Sickle, Wilkinsburg,

Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 20, 1944, Serial No. 545,758

6 Claims.

This invention relates to circuit interrupters in general and, more particularly, to are eX- tinguishing structures therefor.

A general object of my invention is to provide an improved circuit interrupter which will more effectively interrupt the circuit passing therethrough than has heretofore been achieved.

Another object is to provide an improved circuit interrupter of the type establishing both a pressure-generating are and an interrupting arc in which piston means are associated with the intermediate contact to determine the time of formation of the interrupting arc.

Another object is to provide an improved circuit interrupter of the type establishing a pressure-generating arc and an interrupting arc and to have a variable gap between the pressuregencrating contacts. I have this gap length determined in accordance with the pressure generated at the pressure-generating arc.

Another object is to provide an improved circuit interrupter of the foregoing type in which upon excessive pressure conditions the pressuregenerating gap will automatically be shortened.

Further objects and advantages will readily become apparent upon a reading of the following specification taken in conjunction with the drawings, in which:

Figure 1 is an elevational view of a circuit interrupter embodying my invention and shown in the closed circuit position;

Fig. 2 is an enlarged vertical sectional View taken through the left-hand arc extinguishing unit of Fig. l, the contacts being shown in the closed circuit position;

Fig. 3 is a view similar to Fig. 2 but showing the disposition of the moving parts at an intermediate point in the opening operation;

Fig. 4 is a sectional view taken along the line IV-IV of Fig. 2; and

Fig. 5 is a sectional View taken along the line V-V of Fig. 2.

Referring to the drawings and more particularly to Fig. 1 thereof, the reference numeral l designates a tank in which a suitable arc 6X- tinguishing fluid 2, in this instance circuit breaker oil, fills the tank I to the level 3. Depending from the cover 4 of the tank I are two insulating bushings 5, 6 through which extend terminal studs 1, 8. Threadedly secured at the lower end of the terminal studs 1, 8 are contact feet 3, It which support identical arc extinguishing units generally designated by the reference numeral l l.

Electrically interconnecting the two units H is a conducting bridging member :2 reciprocally 2 actuated in a vertical direction by an insulating operating rod l3. At the opposed outer ends of the bridging member 52 are movable rodshaped contacts M, [5.

Referring to Fig. 2 it will be observed that a relatively stationary contact I6 is threadedly secured to the contact foot 9. The contact foot 9 has a downwardly depending flange portion ll threaded at H] which serves to secure in position an insulating cylindrical casing IS. The lower portion of the casing H] is threaded at 29 and supports a closure plate 2|.

Cooperating with the stationary contact Hi to establish a pressure-generating are 22, more clearly shown in Fig. 3, is an intermediate contact structure generally designated by the reference numeral 23. Thus the pair of contacts i6, 23 separate to establish a pressure-generating are within the confined chamber 48, see Fig. 3. In this instance, the contact structure 23 comprises four segmental contacts 24 radially biased inwardly by a plurality of compression springs 25. The outer ends of the compression springs 25 seat against the inner wall of a housing 25, which is preferably composed of conducting maerial. Serving as a stop for the inward motion of the contacts 24 is a portion 2! integrally formed with the housing 26 and hav'ng four support members 28 extending therebetween, as more clearly shown in Fig. 5.

The movable or third rod-shaped contact i4 cooperates with the intermediate contact 23 or one of the pair of contacts to establish an interrupting or second serially related arc designated by the reference numeral 29 in Fig. 3. Op-

eratively connected with the intermediate con tact 23 are piston means in this instance comprising a piston member 30 secured to and movable with the intermediate contact 23 by four support members 35. The supporting means includes four support members 3! integrally formed with the piston 39 and with an orifice 32 defined by a cylindrical orifice member Vents or apertures constituting Venting means 34 are provided through the wall of the casing it to eliminate back pressure acting on the upper side of the annular piston ea. Biasing means including a compression spring 35 biases the piston 39 in a downwardly direction. The piston member 3a is guided by a downwardly extending cylindrical portion 3 5 in this instance integrally formed with the contact foot t. The upper portion 37 of the piston 36 is threaded, as at 38, and makes threaded engagement with a plate 39 having apertures extending therethrough.

Positioned in a recess 4| formed in the casing i9 is an annular guide insulating member 42 secured in place by a spacer ring 43 and having an aperture 44 extending therethrough through which may move the cylindrical member 33. Apertures 45 are preferably provided in the closure plate 2| which also has a centrally formed aperture 46 provided therethrough, through which moves the movable contact M.

The operation of the interrupter will now be explained. In the closed circuit position as shown by the full lines in Fig. 1 and in Fig. 2, the

electrical circuit therethrough comprises terminal stud l, Contact foot 9, stationary contact l6, intermediate contact 23, lower movable contact l4, bridging member i2, through the right-hand unit H in an identical manner to the right-hand terminal stud 8.

To open the breaker the operating rod I3 is moved downwardly. This lowers the movable contact H to permit the compression spring 35 to force the intermediate contact structure 23 downwardly with the movable contact l4 thus causing a separation between the intermediate contact 23 and the stationary contact 16 to draw a pressure-generating are 22 within the confined chamber 48. This downward movement of the intermediate Contact 23 and the movable contact l4 continues until the pressure generated at the pressure-generating arc 22 acting through the passage means 49 on the lower surface of the piston 30 is sufficient to halt the downward motion of the piston member 30, at which time a separation takes place between the intermediate contact 23 and the contact 14, thereby establishing an interrupting are 29 more clearly shown in Fig. 3. Thus separation of the intermediate contact 23 from the movable contact I4 only takes place after a predetermined pressure exists within the casing [9. When this predetermined pressure does exist only then is there a separation between the contacts I4, 23 to draw the interrupting arc 29.

When the interrupting are 29 is drawn it is subjected to a fluid blast through the orifice 32 through which the interrupting are 29 is drawn. This fluid blast arises since I have provided passage means 49 permitting fluid under pressure created at the pressure-generating are 22 within the confined chamber 48 to flow toward the interrupting are 29 and out of the casing l9 through the orifice 32. The passage means 49 is formed by the spaces between the segmental contacts 24 in the intermediate contact structure 23 noting Fig. 5. The pressure may also act downwardly through the apertures 49 in the plate 39. Should the pressure resulting from the drawing of the two arcs 22, 29 rise to dangerous values this will cause the piston member 33 to be moved upwardly thereby shortening the gap between the contacts l6 and 23 thereby shortening the pressure-generating arc 22. Upon excessive pressures being attained within the casing [9 there may result even reclosure of the contacts H3, 23.

It will be observed that the orifice member 33 moves with the piston 30 and the intermediate contact structure 23 to thus maintain, regardless of current values, the proper distance between the orifice 32 and the intermediate contact 23.

A number of types of circuit interrupters have been built with one break generating gas from the switching fluid to produce extinction at the other gap. If the gas producing gap is sufficiently long to produce adequate pressure and gas for low currents, it establishes the upper limit by producing destructive pressures on high current. This device provides a variable gap, the length of which is reduced by the pressure of the high current arcs.

When the moving contact is withdrawn, the intermediate contact under the action of the spring 35 follows and thus draws the pressuregenerating arc 22. The arc 22 produces pressure to force the extinguishing medium across the gap between the moving contact l4 and the intermediate contact 23 when they do separate. When adequate pressure is obtained the pressure acting upon the piston 36 retards the piston and intermediate contact 23 so that only then the interrupting arc is drawn by the main moving contact I4 and is extinguished. The higher the current, the shorter the pressure-generating arc 22 need be and the more quickly the interrupting are 29 will be drawn and extinguished.

To produce the most favorable conditions for interruption, the best spacing between the intermediate contacts 23 and the throat 32 of the 1 nber is maintained by having them both together with the piston 30 so that their "ciative position does not depend upon the value current (as it would if the throat 32 were sta- J From the foregoing description it will a parent that my invention consists in the of varying the length of the gas producin accordance with the current (or presa and in maintaining most favorable relas between the intermediate contact 23 and the throat of the orifice member 33.

From the foregoing description it will be readily apparent that I have provided an improved circuit interrupter of the type establishing both a pressure-generating arc and an interrupting arc in \v. 5 he length of the pressure-generating arc is determined by the pressure conditions existing in the interrupting unit. The arcs are drawn in sequence, the interrupting are only being drawn following the attainment of a predetermined pressure within the interrupting unit sim"ic..cntly adequate to insure interruption of the interrupting are.

In the full open circuit position of the interrupter the movable contacts l4, l5 travel out of the casings 59 to a position indicated by the dotted lines in Fig. l. The piston 30 and orifice member 33 move downwardly until the support members 35 strilze the annular member 42. Fresh oil may then enter the casing l3 through the apertures 45, 45 in plate 2i and through the orifice into the interior of the casing l9.

During the closing stroke the movable contacts M, iii are moved upwardly. Referring to Fig. 2 the movable contact 14 enters the aperture 46, moves through the orifice 32, engaging the segmental contacts 24 until the contact 14 strikes the portion 21, at which time the contact II. intermediate contact 23 and piston 30 move upwardly together as a unit until contact is made between the stationary contact 15 and the intermediate contact at which time the circuit is completed through the interrupter and the compression spring 35 is charged.

Although I have shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration and that changes and modifications may readily be made by those skilled in the art without cleparting from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, means defining a confined chamber, a pair of contacts separable to establish an are within the confined chamber, a third contact separable from one contact of said pair of contacts to establish a second serial- 1y related are, means for causing opening movement of the third contact, a piston member operatively connected to and movable with said one contact, means biasing said one contact and the piston member to move and follow the third contact during the initial portion of the opening operation, venting means at the side of the piston member which permits movement against its biasing means, passage means extending between the other side of the piston member and the are established between the said pair of contacts so that the pressure generated will act on said pistc-n member and stop said one contact from following in contacting engagement with the third contact after the pressure is suflicient to overcome the biasing action. exerted by the biasing means and thereby cause separation between the third contact and said one contact, and said passage means also extending from the arc established between said pair of contacts to the are drawn by separation of the third contact from said one contact to extinguish it by a blast of fiuid.

2. In a circuit interrupter, means defining a confined chamber, a pair of contacts separable to establish an arc within the confined chamber, a third contact separable from one contact of said pair of contacts to establish a second serially re lated are, means for causing opening movement of the third contact, a piston member operatively connected to and movable with said one member to move and follow the third contact during the initial portion of the opening operatic-n, venting means at the side of the piston member which permits movement against its biasing means, a member having an orifice through which the second serially related arc is rhewn, means supporting the orifice member from one contact so as to be spaced a fixed distance therefrom. passage means extending between the other side of the piston member and the are established between the said pair of contacts so that the pressure generated will act on said piston member and stop said one contact from following in contacting engagement with the third contact after the pressure is sufiicient to overcome the biasing action exerted by the means and thereby cause separation between the third contact and said one contact, and passage means also extending from the are established between said pair of contacts to the are drawn by separation of the third contact from said one contact through the orifice to extinguish it by a blast of fluid.

3. In a circuit interrupter, a cylindrical casing, means defining a confined chamber within the casing, a pair of contacts separable to establish an are within the confined chamber, a third contact separable from one contact of said pair of contacts to establish a second serially related are, means for causing opening movement of the third contact, an annular piston member guided interiorly of the cylindrical casing and operatively connected to said one contact, spring means biasing said one contact and the piston member to move and follow the third contact durin the initial portion of the opening operation, apertures provided through the wall of the casing to vent the side of the piston member which permits movement against its spring means, passage uni w means extending between the other side of the piston member and the are established between the said pair of contacts so that the pressure generated will act on said piston member and stop said one contact from following in contacting engagement with the third contact after the pressure is sufiicient to overcome the biasing action exerted by the spring means and thereby cause separation between the third contact and said one contact, and said passage means also extending from the arc established between said pair of contacts to the are drawn by separation of the third contact from said one contact to extinguish it by a blast of fluid.

4. In a circuit interrupter, a cylindrical casing, means defining a confined chamber within the casing, a pair of contacts separable to establish an arc within the confined chamber, a third contact separable from one contact of said pair of contacts to establish a second serially related are, means defining an orifice member carried by the said one contact through which the second serially related arc is drawn, means for causing opening movement of the third contact, an annular piston member guided interiorly of the cylindrical casing and operatively connected to said one contact, spring means biasing said one contact and the piston member to move and follow the third contact during the initial portion of the opening operation, apertures provided through the wall of thecasing to vent the side of the piston member which permits movement against its spring means, passage means extending between the other side of the piston member and the are established between the said pair of contacts so that the pressure generated will act on said piston member and stop said one contact from following in contacting engagement with the third contact after the pressure is sufficient to overcome the biasing action exerted by the spring means and thereby cause separation between the third contact and said one contact, and said passage means also extending from the are established between said pair of contacts to the are drawn by separation of the third contact from said one contact to extinguish it by a blast of fluid.

5. In a circuit interrupter of the fluid blast type, a relatively stationary contact, an intermediate contact cooperable therewith to draw an are, a movable contact cooperable with the intermediate contact to establish a second serially related arc, means defining an orifice carried by the intermediate contact and through which the second serially related arc is drawn,

and passage means extending from the first mentioned are into the orifice to effect the extinction therein of the second serially related are by the blast of fluid from the first-mentioned are.

6. In a circuit interrupter of the liquid break type, a cylindrical casing immersed in a suitable arc extinguishing liquid, an annular piston member guided by the interior wall of the casing, apertures through the wall of the casin to vent the space above the upper side of the piston mem ber, a relatively stationary contact disposed at the upper end of the casing, an intermediate contact separable from the stationary contact to establish a pressure-generating are within the upper end of the casing, means attaching the piston to move with the intermediate contact, a spring biasing the piston and intermediate contact downwardly, a member having an orifice carried by the piston member, a rod-shaped movable contact movable through the orifice to en- The following references are of record in REFERENCES CITED file of this patent:

UNITED STATES PATENTS Number Re. 18,257 2,075,749 10 2,077,338

the

Name Date Paul Nov. 24, 1931 Paul Mar. 30, 1937 Lingel et al Apr. 13, 1937 

